The goal of this research program is to develop a novel optical fiber that will enable wavelength tunable, all-fiber, energetic femtosecond sources, and then demonstrate the value of the proposed laser system for biomedical applications. The innovation of the proposed femtosecond sources is based on a new class of optical fiber that was recently demonstrated, where, for the first time, a large anomalous dispersion was achieved at wavelengths below 1300 nm in an all-silica fiber. The proposed research concentrates on the development of a novel higher order mode fiber for wavelength tuning based on the concept of soliton self-frequency shift. Leveraging the highly mature and integrated techniques that have been developed for the telecommunications industry, we aim to create two "telecom grade" femtosecond sources that are truly robust and turn-key, and tailored specifically for biomedical research and clinical diagnostics. This research program involves close collaboration between Cornell University (Dr. Xu) and fiber manufacturer OFS-Fitel (Dr. Ramachandran). The industry-academia collaboration proposed in this program strongly couples biomedical optics and the fiber-optic communication industry, creating great synergies between two seemingly divergent fields and providing new opportunities for innovation in biomedical research. The ultimate aim of this exploratory instrumentation grant is to establish a novel methodology for wavelength tunable, energetic femtosecond fiber lasers for biomedical applications.The proposed program, if successfully completed, leads to a novel, wavelength tunable, femtosecond fiber laser that will have a broad impact on biomedical applications of ultrafast technologies. There are significant practical advantages offered by the all-fiber configuration, such as compact foot print, robust operation, and operational safety in a clinical environment. The successful completion of this research program will make femtosecond sources truly widely accessible to biologists and medical researchers and practitioner. [unreadable] [unreadable] [unreadable]